Read image data from a vector of bytes

cargo test passes

src/lib.rs

@@ -27,7 +27,7 @@
 extern crate libc;
 
 use std::ffi::CString;
-use libc::{c_uint, size_t, c_double};
+use libc::{c_uint, size_t, c_double, c_void};
 use filters::FilterType;
 
 mod bindings;
@@ -59,10 +59,19 @@ impl MagickWand {
         }
     }
 
-    // TODO: make a Rustic wrapper for reading a blob from bytes
-    // pub fn MagickReadImageBlob(arg1: *mut MagickWand,
-    //                            arg2: *const ::libc::c_void, arg3: size_t)
-    //  -> MagickBooleanType;
+    /// Read the image data from the vector of bytes.
+    pub fn read_image_blob(&self, data: Vec<u8>) -> Result<(), &'static str> {
+        let int_slice = &data[..];
+        let size = data.len();
+        let result = unsafe {
+            bindings::MagickReadImageBlob(
+                self.wand, int_slice.as_ptr() as *const c_void, size as u64)
+        };
+        match result {
+            bindings::MagickTrue => Ok(()),
+            _ => Err("failed to read image")
+        }
+    }
 
     /// Retrieve the width of the image.
     pub fn get_image_width(&self) -> usize {

tests/lib.rs

@@ -19,6 +19,10 @@ extern crate magick_rust;
 use magick_rust::{MagickWand, magick_wand_genesis};
 use magick_rust::filters::{FilterType};
 
+use std::error::Error;
+use std::fs::File;
+use std::io::Read;
+use std::path::Path;
 use std::sync::{Once, ONCE_INIT};
 
 // Used to make sure MagickWand is initialized exactly once. Note that we
@@ -54,3 +58,25 @@ fn test_resize_image() {
     assert_eq!(256, wand.get_image_width());
     assert_eq!(192, wand.get_image_height());
 }
+
+#[test]
+fn test_read_from_blob() {
+    START.call_once(|| {
+        magick_wand_genesis();
+    });
+    let wand = MagickWand::new();
+
+    let path = Path::new("tests/data/IMG_5745.JPG");
+    let mut file = match File::open(&path) {
+        Err(why) => panic!("couldn't open file: {}", Error::description(&why)),
+        Ok(file) => file
+    };
+    let mut data: Vec<u8> = Vec::new();
+    match file.read_to_end(&mut data) {
+        Err(why) => panic!("couldn't read file: {}", Error::description(&why)),
+        Ok(_) => ()
+    };
+    assert!(wand.read_image_blob(data).is_ok());
+    assert_eq!(512, wand.get_image_width());
+    assert_eq!(384, wand.get_image_height());
+}